Background/Purpose:

Antimalarials (AMs) have shown to exert a thromboprotective effect in systemic lupus erythematosus (SLE), but studies thus far have been limited to North American and European patients. This study was conducted to assess whether a similar effect is observed in Latin American patients with SLE.

Methods:

SLE patients with a recent diagnosis (<=2 years) recruited and followed longitudinally as part of the GLADEL cohort were examined to establish risk factors for thrombotic events (TEs) and the possible preventive role of AMs. The outcome variable was defined as the presence of an arterial or venous thrombotic event during follow up. AM use was considered present (ever used) or absent (never used). After controlling for possible confounding variables identified in univariable analysis, the use of AM drugs was assessed for its effects on the development of TEs in cohort patients and by Cox proportional hazards regression analyses.

Results:

Of the 1,480 patients included in the GLADEL cohort, 1,213 (82%) were considered AMs users. Thrombosis occurred in 87 (5.9%) of the patients during a median follow up time of 64 (range 1298) months. After adjustment for potential confounders in the Cox proportional hazards regression model, AM use was associated with a 39% reduction in the rate of TEs (hazard ratio 0.61, 95% CI 0.400.95). Other variables significantly associated with TEs are depicted in Table 1.

Table 1. Effects of AMs drugs on the development of TEs in SLE patients from the GLADEL cohort by multivariable Cox proportional hazards regression analysis.

Parameter

HR

95% CI

P Value

Antimalarial use

0.612

0.40

0.95

0.0288

Female sex

0.486

0.28

0.84

0.0096

Antiphospholipid antibodies

1.689

1.01

2.82

0.0443

Any Hospitalization

2.200

1.39

3.48

0.0008

Aspirin/Anticoagulant use

2.156

1.14

4.07

0.0181

Thrombosis Previous to SLE Diagnosis

3.688

1.85

7.35

0.0002

Conclusion:

After adjusting for possible confounding factors related to AM use, a clear protective effect of AM in the development of TEs in SLE patients from this Latin American cohort was observed.